Re: Why is this not autovivifying?

Autovivification happens in an lvalue context, but you're using it only as an rvalue in the else branch of your accessors.

Update: And just to be (more :) pedantic, this isn't strictly speaking autovivification that you're expecting (that's automatically creating a reference to the proper data type when undef is used in an lvalue context). What you're seeing is access to a non-existent hash slot not creating an entry in that slot.

Comment on Re: Why is this not autovivifying?

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Re^2: Why is this not autovivifying? by blahblah (Friar) on Apr 02, 2007 at 15:47 UTC
Ah. Thank you very much Fletch for the excellent and succinct explanation. I'm really disappointed I didn't know that before - and judging from the -1 vote I'm not the only one disappointed that I didn't know that before. Thanks!	[reply]
Re^2: Why is this not autovivifying? by ikegami (Patriarch) on Apr 03, 2007 at 01:06 UTC
Not at all. An lvalue context is not required. `print $hash{foo}{bar}; # Autovivifies $hash{foo}` [download]	[reply] [d/l]
Re^3: Why is this not autovivifying? by Fletch (Bishop) on Apr 03, 2007 at 13:21 UTC
Oop, quite right. The presence of 'lvalue' in perlref was still in my mind. It's more like 'the use of an undef value (retrieved from somewhere which could be an lvalue; i.e. `$a->{"foo"}` will, `undef->{"foo"}` won't) to the left of a `->` (implicit or explicit) attempting to dereference the value'.	[reply] [d/l] [select]